But the problem with experience is that anyone can claim they have it at something. Until there's a subjective test, its really meaningless.
Really, so someone who just started somehow has experience with exactly the way its done at their new company?
Even if they worked at a previous company that used the exact same toolkit and software packages, there will be some learning curve with the way this company does things. Even down to how your manager/supervisor wants things done. Take an exact employee and giving them an additional year's experience with that company's systems and there is no way you can say they won't be any more productive.
EDIT: How do you even know the person who just started is even capable?
At my current job, I will gladly take someone with less overall experience in this type of job but more experience with my specific client. Its so much easier when someone already knows why something works a certain way rather than having to explain to them or have them figure it out.
Say I'm a manager and I have 2 choices. Do I want to pay 50k to someone from another company with what seems to have the same qualifications and might turn out to be a dud or pay someone 55k who already knows what they're doing and how I want them to do it and I know what to expect from them. I've probably also built a working relationship with them. Tough choice.